Process for the production of sulphuric acid



ON-THE- H f EL, OFNUREMBERG-DOOS, AND HANS KLENCMZ, 0E a GER/M.

PROCESS FOR THE IPRODUCTION OF SULP'AA Application filed may 3,

180 Drawing.

To all whom it may concern Be i known that we, Tnnonon SCHMIEDEL and HANS KLENCKE, citizens of the German Republic, and residing at Nuremberg-Boos, Herderstrasse 3, and Frankfort-on-the-Main, Schwanthalerstrasse 72, have invented certain new and useful. Improvements in Processes for the Production of Sulphuric Acid, of which the following is a specification.

This invention relates to a process for the production of sulphuric acid, and is. an improvement in or modification of the process described and claimed in the specification of the Patent No. 1,399,526 (Serial No. 403,417) hereinafter called the main patent.

In the specification of said main patent, a recess for the production of sulphuric acid without the usual lead. chambers or towers has been described, according to $0 which the whole process of the formation'of and huric acid is efiected in a shorter space and time than was hitherto possible. Said process consists in'bringing a solution of nitrosyl sulphuric acid in sulphuric acid aving a minimum density of 54 B., in the form of a fine spray or mist, into intimate contact with gases containing sulphur dioxide, the quantity employed'being such that, throughout the system, the. said solution nowhere loses its activity to such an extent as to become incapable of oxidizing said sulphuric acid, in other words, that it always contains nitrosyl sulphuric acid. The

process further consists in thereafter withdrawing an amount of said circulating nitrosyl sulphuric acid, corresponding approximately to the amount of sulphuric acid produced, and in denitrating same, in any suitahlg manner, to form commercial sulphuric ac1 In the specification of said main patent, it is mentioned that the strength of the nitrosyl sulphuric acid should be preferably within the limits of 54-58" Be.

Accordingly, the resulting commercial sulphuric acid will also be within these limits of concentration. However, therie are numerous cases in which an acid stronger than 58 as, is required. The endeavour was, therefore, in such cases to obtain by t process also an acid having a higher ure of concentration. Inasmuch as a uniform concentration of acid is mamtamed generally and inasmuch as for w. concentration of 1922. Serial No. 558,273.

the acid to increase owing to'the formation of sulphuric acid, it was hitherto the practice, in order to'maintain the desired concentration of the acid, to introduce a corre- This acid of higher concentration has a stronger wer for dissolving nitrcsyl sulphuric aeldgases. However, it has also a stronger aflimty for the water required for the formation of sulphuric acid. If, there fore, it is desired to work the process with an acid of higher concentration, it is necessary when a certain concentration has been reached to provide means for lowering the aflinity for the water required for the formation of sulphuric acid. This is efiected in accordance with the present invention by maintainin the wrature of the acid somewhat igher. remarked that for a limited increase in the concentration of the acid, say for example, from 58 Be. to about 59 B., such an increase of temperature is not required, b ut only if it is intended to work with densltles of 60 B. and'over. The increase of temperature is cfiected by merely lessenmg the cooling of the acid which is automatically heated by the heat ofreactlon.

A further possibility of working w th an acid of higher concentration cons sts 1n us-' ing the so-called double-circuit irrigation. This consists in irrigating with an acid of a high degree of concentration, the fore art of the plant, that is those-mixing cha n rs which the gases containing sulphur dioxide enter first, as well as the rear part of the plant, that is the mixing chambers, at the exit, whilst the middle part of the plat is irrigated with a weaker acld (above 54 It is of course necessary to collect both acids in difierent receptacles so that cannot mix. Theeii'ect of this kind of irrigation is that the high grade acid very completely and quickly absorbs the nltrosyl suiphuric acid gases in the mixing chamhers through which said hlgh grade acid thus forming nitrosyl sulphuric acid oi high percentage. Naturally, in consequence of its high content of nitrosyl, th s high ade nitrosyl sulphuric acid efiects a very fight oxidizing action, in the first apparatus, andthus further accelerates '0:- a: th

owever, it should he acid in the middle parts of the plant exercises a favourable lnfluenceon the forma- I middle chambers. Y

, the sulphur in the mixing device against the gases.

The carrying out of the process with acid of difierent degrees of concentration now en ables a further development which effects a surprisingly great acceleration of the progress of the reaction. This new way of carrying out the process consists in the following Assumin ing devices process; the gases contaming dioxide enter the first mixing chamber and the mixing devices are irrigated from a coma ilgnt of several units (mixto used for carrying out the mon tank, containing a solution of nitrosyl v sulphuric acid in sulphuric acid, in such a manner that a certain amount of nitrosyl sulphuric acid flows into each mixing device and that thenitr l sulphuric ac1d flowing on from each mlxing device is returned to one common tank, in which the acid is mixed again and returned to the cycle of the system. So far, .the procedure corresponds exactly the way the process has been hitherto carried out, but whereas, according to this previous way of carrying out the process, the gases next pass through a number of mixing devices and meet everywhere nitrosyl sulphuric acid of the same concentration until their content of sul hur dioxide has been practically complete y oxidized, and simultaneously the nitrous oxides which have entered the gas as a result of the reaction, have been takenup by the irrigating acid, the new Way of carrying out the proc ess introduces a modification, after a certain number of m'ixingdevices, about three I or more have been traversed, in so far that the concentration of the nitrosyl sulphuric acid is reduced, by the sudden addition of the entire water required for the process, to such an extent that it is freed very considerably although not completely, from its contents in nitrosyl sulphuric :acid, i. e., until it has been practically completely denitrated. Consequently, large volume of nitrous vapou enter the gas and thereby efl'ect very rap d and complete oxidation of hxide still contained therein,

this action being further supported by the large addition of water to the acid spra y gd e gases leave themixing device in which this other suitable manner.

sulphur process'is eflected, practically free from sulr phur dioxide, but contain instead, a lugh percentage of nitrous oxide. Consequently contents in oxygen to the nitrogen compounds, which is done by correspondingly retarding the movement of the gases. T 's is effected either by introducing the gases, after leaving the last mixing device, into a large empty chamber or by passing them through a sufliciently long pipe or in any This is succeeded by an absorption installation of any kind in which the gases give up their contents in nitrogen-oxygen compounds to strong sulphuric 'acid and thereby form nitrosyl sulphuric acid. For thispurpose devices of a known kind irrigated with strong sulphuric acid which may contain nitrosyl sul huric acid, or boxes containing roller distri uting devlces, may be used.

In the new way of carrying out the process, the main part of the sulphur dioxide content, as hitherto, is rapidly worked up in the first mixing chambers of the installation, and the diluted remainder is almost instantaneously oxidized by the sudden disengage.- ment of the nitrogen oxide compounds liberated by means of water, so that further mixing devices are dispensed with.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that What We claim is:-

1. A process for manufacturing sulphuric acid without the custeman -leadchambers or reaction towers, comprising the bringing to gether of a solution of nitrosyl sulphuric acid in sul huric in very fine subdivision and S -contain e ases with the help of a mechanical inixin; @BV'iCQ, the solution being used in an amount such that at no ring sulphuric chambers or e bringing to of a mechanical mixing device, the solution being used in an amount such that point in the plant does he solution, as a result of the de-nitratio oxidizing S0 the acid sulphuric acid havin that corresponding to a ing the nitrosyl acid at an temperature.

'rosyl sulphuric v tine suedwr th solution for nitrogen-oxygen com nuance 3. In the process of claim 1, maintaining a portion of the nitrosyl sulphuric acid solution at a lower concentration with respect to sulphuric acid and at a higher concentration with respect to water, than the remaining portions of the nitrosyl sulphuric acid solution.

4. A "process for manufacturing sulphiiric acid without the customary lead chambers or reaction towers, comprising the bringing together of a solution of nitrosyl sulphuric acid in sulphuric acid in very fine subdivision, and sO -containing gases with the help of a mechanical mixing device, a portion of the nitrosyl sulphuric acid solution being maintained at a concentration corresponding to above about 54 B. and being intimately mixed with the gases richer in $0 and a second portion of the nitrosyl sulphuric acid solution being subjected to the action of water in such amounts that the solubility at un s is substantially diminished where y the nitrous gases are rapidly liberated from the solution and enter the gas mixture and rapidly oxidize the remaining sulphur dioxide contained therein, and whereby the gas mixture thus produced, which at this stage contains relatively a very small proportion ofsulphur dioxide, readily oxidizes the nitrogen compounds and subsequently absorbin the oxidized nitrogen com ounds in a su phuric acid solution producing nitrosyl sulphuric acid.

5. In a process of producing sullpehuric acid without the customary lead chain rs or reaction towers, the steps which com rise intimately mixing gases relatively ric in SO with nitrosyl sulphuric acid solution of relatively high concentration with respect to nitrosyl sulphuric acid and subsequently subfooting the gases resulting from this step to the action of a nitrcsyl sulphuric acid solution of lower concentration with respect to nitrosyl sulphuric acid and of higher concentration with res set to water than in the preceding step an then subsequently subecting the gases thus produced to the action of-nitrosyl sulphuric acid solution having a hi her concentration with respect to nitrosyl phuric acid and a lower concentration with respect to water than in the preceding step.

64 In a process of producing sulphuric acid without the customary lead chambers or reaction towers, the steps which comprise intimately mixinggases relatively rich in S0; with nitrosyl sulphuric acid solution of relatively high concentration with respect to nitrosvl sulphuric acid and'subsequently subjecting the gaw resulting from this step to the action of a nitrosyl sulphuric acid solution of lower concentration with respect to nitrosyl sulphuric acid and of higher concentration with t to water than in the preceding step and then subsequently subjecting the gases thus produced to the action of nitrosyl sulphuric acid solution having a higher concentration with respect to nitrosyl sulphuric acid and a lower concentration with respect to water than in the preceding step, and subsequently de-nitrating an amount of the nitrosyl sulphuric acid correspondingto the production of sulphuric acid and1 separating the de-nitrated sulphuric aci 7. In a rocess of producing sulphuricacid without t e customary lead chambers 01 reaction towers, the steps which comprise intimately mixing gases relatively rich in S0 with nitrosyl sulphuric acid solution of relatively hi h concentration with respect to nitrosyl su phuric acid and subsequently subjecting the gases resulting from this step to the action of a nitrosyl sulphuric acid solution of lower concentration with respect to nitrosyl sulphuric acid and a higher concentration with respect to water than in the preceding step and then subsequently subjecting the gases thus produced to the action of nitrosyl sulphuric acid solution having a higher concentration with respect to nitrosyl sulphuric acid and a. lower concentration with respect to water than in the preceding step, and subsequently de-nitrating an amount of the nitrosyl sulphuric acid approximately corresponding to the production of sulphuric acid and separating the de-nitrated sulphuric acid.

8. In .a process of producing sulphuric acid without the customary lead chambers or reaction towers, the steps which comprise intimately mixing gases relatively rich in S0, with nitrosyl sulphuric acid solution of relatively high concentration with respect to nitrosyl sulphuric acid and subsequently subjecting the gases resultin from this step to the action of a nitrosyl su phuric acid solution of lower concentration with respect to nitrosyl sulphuric acid and of higher concentration with respect to water than in the preceding step and subsequently subjecting the gases thus produced to the action of nitrosyl' sulphuric acid solution having a higher concentration with respect to nitrosyl sulphuric acid and a lower concentration with respect to water than in the preceding step, and subsequently denitrating by means of fresh SQ -cOntaining gases an amount of the nitrosyl sulphuric acid approximately corres ondlng to the production of sulphuric aci and separating the de-nitrated sulphurlc acid.

9. In the process of manufacturing sulphuric acid from gases containing sulphur dioxide without the aid of customary lead chambers or reaction towers, rapidly oxidizing the main portion of the SlllPlluldlOXidQ contained) in the gases and subsequently oxidizing the diluted remainder f th 1;

,phur dioxide bysubjecting them to the action pf nitrogen-oxygen compounds 'liber ated from a nitrosyl sulphuric acid solution by the addition of water thereto.

10. In the process of manufacturing sulphuric acid from gases containing sulphur dioxide without the aid of customary lead chambers or reaction towers, rapidly oxidizing the main portion of the sulphur dioxide contatined in the gases and subsequently oxidizing the diluted remainder of the sulphur dioxide by subjecting them to the action of nitrogen-oxygen compounds liberated from a nitrosyl sulphuric acid solution by the addition of water thereto and subsequently oxidizing the gases thus produced by means of oxygen and subsequently subjecting the oxidized gases thus produced to the action of the sulphuric-acid solution to absorb'the oxidized nitrogen oxide oxide compounds.

11. In the process of manufacturing sulphuric acid from gases containing sulphur dioxide without the aid of customary lead chambers or reaction towers, rapidly oxidizing the main portion of the sulphur dioxide contained in the gases and subsequentl oxidizing the diluted remainder of the su phur dioxide by subjecting them tothe action of nitrogen-oxygen compounds liber ated from a nitrosyl sulphuric acid solution by the addition of water thereto and subsequently oxidizing the gases thus produced by means of oxygen and subsequently subjecting the oxidized gases thus'produced to the action of sulphuric acid-containing solution to absorb the! oxidized nitrogen oxide com unds.

12. In t e rocess of manufacturing sulphuric acid om gases containing sulphur dioxide. without the aid of customary lead chambers or reaction towers, rapidly oxidiz-' ing the main tportion of the sulphur dioxide contained in the gases and su uentl oxidizing the diluted remainder oft e s phur dioxide by subjecting them to the action of nitrogen-o gen com ounds liberated from a nitrosy sulphuric acid solu.- tion by the addition of water thereto and subsequently oxidizing the gases thus produced by means of oxygen and subsequently subjecting the oxidized gases thus produced to the action of sulphuric acid-containing solution to absorb the oxidized nitrogen oxide compounds, and de-nitrating an amount of the nitrosyl sulphuric acid solution corresponding to the production of sulphuric acid.

13. In the rocess of manufacturing sulphuric acid rom gases containing sulphur dioxide withoutthe aid of customary lead chambers or reaction towers, rapidly oxidizing the main portion of the sulphur dioxide contained in [the gases and subse uentlq' oxidizing the diluted remainder of t e su phur 'dioxide by subjecting them to the action of nitroge -oxygen compounds liberated' from a nitrosyl sulphuric acid solution by the addition of water thereto and subsequently oxidizing thegases thus produced by means of oxygen and subsequently subjecting the oxidized gases thus produced to the action of sulphuric acid-containing solutions to absorb the oxidized nitrogen oxide compounds and denitratin an amount of the nitrosyl sulphuric aci solution corresponding to the production of sulphuric acid and separating the de-nitrated sulphuric acid.

In testimony whereof we afiix our signatures in presence of two witnesses.

PH. H. THEODOR SCHMIEDEL. HANS KLENCKE. Witnesses: Roamrr ENGLER, BAsIL E. SAVARD. 

